An Electrically Isolated Low Power LED Driver Offering Power Factor Correction with Ameliorated Mains Current THD

Abstract

This paper proposes an efficient design of an electrically isolated low power (12w) light emitting diode (LED) driver with active power factor controller (PFC) based on buck converter topology. The presented system comprises a rectifier-fed-PFC unit which reduces the harmonic distortion of the mains (230V r.m.s.) line current by improving the sending-end power factor. There is a dc-link-inverter which consists of a soft switched buck converter and a parallel-loaded series L-C resonant inverter. At the receiving-end, there is a high frequency transformer provided isolation and a rectifier to feed appropriate voltage and current to a 12w LED lighting load. The switching converters are controlled by pulse width modulation (PWM) signals of 20kHz. The framework has been simulated on PLECS software. The total harmonic distortion (THD) of the mains line current is approximately 10.7904% at 0.9893 sending-end power factor whereas the third harmonic current is 6.1538% and the fifth harmonic current is 5.4557% of the fundamental current and these are less than the recommended values of IEC 61000-3-2. The voltage and current waveforms of every converter stage corroborate the reliability of the proposed work.